The present invention generally relates to a system for recovering and washing tube cleaning plugs and, in particular, relates to one such system including means for maintaining a tube cleaning plug recovery vessel at a preselected depth in the water.
The use of tube cleaning plugs for cleaning the inside of pipes is generally known frown U.S. Pat. No. 4,569,097 entitled Tube Cleaners and issued to Echols on Feb. 11, 1986. Therein recirculating tube cleaning plugs are passed through the tubes of heat exchangers. The tube cleaning plugs are sized and shaped to scrape away slime and sediment from the heat exchanger tubes. Various cleaning plug geometries as discussed.
Further, the recovery and washing of tube cleaning plugs that are discharged from the cooling water pipes of a power plant heat exchanger is known from U.S. Pat. No. 4,696,318 entitled Washing Methods And Apparatus For Heat Exchanger Tube Cleaning Plugs issued on Sep. 29, 1987 and assigned to the assignee hereof. As discussed and described therein floating tube cleaning plugs are introduced into the cooling system of the power plant heat exchanger and are propelled therethrough along with the coolant water. The tube cleaning plugs are sized to scrape away slime, sediment, and the like, from the inside of the heat exchanger condenser tubes as they pass therethrough. The tube cleaning plugs are subsequently discharged into the outflow stream of cooling water. The outflow stream is then typically discharged into a flowing body of water, such as a river, a canal or a stream. The tube cleaning plugs are carried by the flow of the current to a washing station where the tube cleaning plugs are recovered, washed and returned to the pipes of the cooling system. As described therein, the tube cleaning plugs are captured by a floating guideway including outwardly extending booms. Once captured, the tube cleaning plugs are transported to a washing zone by an endless conveyor belt.
One of the drawbacks of present tube cleaning plug recovery and washing systems is that all of the recovery and washing of the tube cleaning plugs occurs in the middle of the flowing stream, or river, of water. As a result, maintenance of the system can be difficult. Further, such systems, because the tube cleaning plugs are guided directly to the endless conveyor belt by the floating guideway, may not efficiently recover those tube cleaning plugs that are bobbing below the surface of the water.
Consequently, a system for receiving and washing tube cleaning plugs that overcomes or avoids these drawbacks is highly desirable not only to reduce maintenance expenses but to ensure recovery of substantially all of the submerged tube cleaning plugs.